Present day computer network architectures have become more and more complex. For example, a network may comprise multiple devices, such as several computer systems, terminals, peripherals, etc., all linked together in order to exchange information and share resources.
Other more complex networks may comprise thousands of devices of varying technical capabilities. In many applications, both local area networks (LANs) and wide area networks (WANs) are connected to form parts of a single network. For example, a network can include a local area component, a wide area component and a component involving communication between computers of different vendors, such as a multi-vendor communication network.
The process for designing computer networks of this type involves a complex -analysis of the customer requirements, the price factor for the various products, the necessary communication lines, and other technical and business considerations. The allocation and planned use of the various resources to support the network needs is now part of the normal capacity planning cycle done by a network manager when setting up the network for a customer.
Because of the potential to form complex networks, a computer network client has a wide range of resources available to supply requested service. This advantage, however, also adds to the problem of networks and resource management. It is therefore desirable to obtain delivery of these services through network service names. A service offers clients capacity to use resources accessible through the network.
In these computer networks, a server, made up of both hardware and software, may be used as an agent between a client and one or more resources to deliver the requested service to the client. The server's software program provides "actions" for a client using one or more resources. These actions, for example, may be transmission of packets over a communication line--a communication server; computations in a problem--a CPU server; information access in a data base--a data base server; network addressing information distributed throughout a network and associated with a requested service--a name server; or other similar and multiple combinations of these functions.
Because networks may include multiple servers generally delivering the same action, a client may access any one of these servers with equal delivery of the action. One of the disadvantages in the prior art is the inability to group these servers providing the same action. This grouping of servers can be seen as a "network service". To overcome shortcomings of the prior art an ideal system for a client to request a service in a complex network should fulfill two requirements. First, the request must include generic accessing of a particular network service name to provide a higher level interface abstraction than the current practice where each client knows of all server possibilities. This has the advantage of substantially simplifying the decision process for the client in the case where multiple servers can deliver the requested service. The only requirement is the network service name rather than the name of each and every server offering the requested service. Second, the requested service must be guaranteed to exist for the client within the server for the duration of a connection.
To supply a service to a client, it is known to use a broker mechanism coupled to the network for scheduling a server to a requesting client. The broker receives a request for access to a service from a client and transmits to the client the name of a server which can deliver the service to the client. One known type of broker operates by assigning an entire server to a client irrespective of the capacity needed by the client.
A problem with the above broker method is the inefficient use of network resources. Prior brokers must continuously monitor all of the servers coupled to the network, increasing the brokers overhead and the network traffic. Because the resource capacities of the servers and the necessary performance level to be allocated to the client are dynamic factors, a broker mechanism which can dynamically allocate servers to clients using a predetermined policy is needed.